MCMI comparisons of cocaine abusers and heroin addicts

Cocaine addicts (N = 107) and opiate addicts (N = 86) in treatment for drug abuse were compared on the MCMI. Univariate analyses revealed that cocaine abusers showed more traits of the antisocial personality style, whereas heroin addicts evinced more problems with anxiety and somatic distress, probably related to residual problems of withdrawal, and alcohol abuse. Multivariate analyses revealed four distinct clusters (MCMI patterns 456', 865', 56', and 8') that aligned by underlying personality style and clinical syndrome expression rather than by drug of choice. Ideographic analyses further demonstrated consistencies in prevalence rates of DSM-III-R personality disorders. Results do not support the pharmacodynamic theory of drug abuse. It was concluded that the similarities in personality between these two groups are greater than their differences.